Combustion apparatus



Malh 21, 1933- D. J. MossHART 1,902,372.v

COMBUSTION APPARATUS Filed Sept. 14, 1929 4 Sheets-Sheet 2 Cb -w ATTORNEY March 21, 1933.

D. J MOSSHART,v

COMBUSTION APPARATUS Filed Sept. 14, 1929 4 Sheets-Sheet 3 INVENTOR D mdd JMosshu'.

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ATTORNEY March 2l, 1933. D. J. MossHAT 1,902,372

COMBUSTION APPARATUS Filed Sept. 14, 1929 4 Sheets-Sheet 4 WITNESS INVENTOR 4 @5.- mmdmssm Cb.q"S.QAxL/M ATTORN EY Patented Mar. 21, 1933 kDOIWAILI) J'.- MOSSHART, OF LANSDOWNE; PENNSYLVANIA, .ASSIGNOR TO WESTING4-V HOUSE ELECTRIC- @c MANUFACTURING COMPANY, A CORPORATION OF PENNS-YL- VANIA coMBUs'rIoN APPARATUS Application led September 14, 1929. Serial No. 392,578.

My invention relates to combustion appara'- tus and more particularly to progressive feed s tokers which include as a part thereof overfeed grate sections of the type comprising a series of grate members disposed V,in end-to-l end relation and extending 1n the direction of fuel feedg'th'eV presentinventlo-n being an improvement on the invention disclosed and claimed in the eopending application of Robert A. F oresman, Serial No. 337,445, filedl February 4, 1929, and assigned to the lVestinghouse Electric & Manufacturing Company.

As is known, in the downwardly-inclined kmultiple retort underfeed Stoker, the green coal is fed into the ends of the several retorts by main rams, and downwardly through the retorts and upwardly and laterally ontothe tuyere green coal nears the incandescent fuel Vbed it becomes heated and the volatiles are driven off. The volatiles combine with the air emitted from the tuyre rows to produce combustion. The remaining solids move laterally on the tuyre rows and the solid carbon content is burned out. The resulting molten ash trickles downwardly through the fuel bed and solidiiies as it comes into contact with the upwardly-moving air stream from the tuyere rows. The ash is moved downwardly of the stoker and to the ash disposal apparatus by virtue of its frictional contact with the downwardly-moving fuel bed. This type of stoker is considered the best for coals containing volatiles, for the reason that the air supply in ample quantities is directly adjacent the point where the volatiles are drivenoi".

From the above description, it may be cony eluded that the multiple retort underfeed Stoker burnscoal in lanes. Lanes of' green coal` are'in and over the retort and lanes of burning solid carbons 'are on the tuyere rows. As the green coal 'changes to solid carbons it is fed laterally onto the .tuyere rows. eye of the observer, thelanes are quite perceptible. Y The lanes in and over'the retorts appear relatively dark, of volatile matter andthe lanes overV the tuyere rows appear light.

rows by secondary rams. Y As theV tained.

To the` due to the presenceV It is necessary that the air through the tuyre rows in ,order'to obtaink enicient combustion, and in order to insure this the movement of the ,fuel bedV must be continuous-and uniform so that' the ash may be carried away` vas it forms.

Should-the ash accumulate at any' Vone point, the ,liow of air'will be restricted at that pointand clinkers will result which will inter-j fer-e with lthe downward movement of thefuel bed and result in considerable trouble `to the operator. In the copending application of Robert A. Foresman, referred to above, av new and improved `form of overfeed grate section is disclosed and claimedwhich repass uniformly *l ceivesy the burning material as itjcomes from the underfeed section, positively carries the burning material and Vash away from the underfeed sectionSO as to maintain the con-V stant "downward Vmov-ement of the fuel bed and agitates `the burning'material, thereby breaking downthellanesand permitting air to penetrate 'and burn out the combustible.l

As theoutput of any particular multiple retort stokeris increased,vcallin`g for Van in creasedcoal feeding rate, more and morecoal is burned and as a result more' and more ash Visdepositedyon the ltuyere ro'ws and has to beA carried down by themoving fuel bed.V Also, as the lengthof the underfeed section is increased, the amountof ash to be moved also increases, Obviously, a pointiwill be're'ached where either the increasedoutput of anypar-k I ticular underfeed stokerfor the increased length ofthe'underfeed Stoker will result in the accumula-tion of ash, in `such amounts that leti'cient combustionjcannot be main- In the copending application of Foresman certain extent; butl is steadily increasing.

of the Foresman type would break up the lanes before the volatiles of the coal are distilled and the green coal would spread over the grate and seriously interfere with the passage of air through the grate and therefore seriously affect combustion. Air will pass through a fuel bed composed of solid carbons and ash by reason of its porous condition; but the fuel bed composed of green coal is of such a dense character as to seriously interfere with the passage of air therethrough.

The demand for larger and longer stokers The underfeed section cannot be built any longer than it is at present for the reason that it will not effectively rid itself of the ash. The length of the overfeed extension grates heretofore known to me are also limited by reason of their construction and operation.

Itis, therefore, an object of this invention to provide a progressive feed stoker which can be constructed of any suitable length, and which will at the same time maintainthe desired lane burning in an extremely edective manner, will provide for the positive movement of the ash and lastly will break down the lanes at the proper point so that the combustible may be effectively burned out before reaching the ash disposal apparatus.

Another object of this invention is to produce an overfeed grate section which is of improved construction and which operates in an improved manner.

. A still further object is toprovide an overfeed grate section of `the undulatory type and alsoto provide an improved means for operating the grate section which operation can be varied to suit the burningV characteristics of different types of fuel. v

These and other objects are eected by my invention, as will be apparent from the following description and claims taken in conneet-ion with the accompanying drawings, and forming a part of this application, in which: v Y Q Fig. 1 is a plan view of my improved progressive feed Stoker; 'Y

Fig. 2 is a longitudinal sectional view of the stoker taken on line line II-II of Fig. 1; i Fig. 3 is a transverse sectional view taken n the line III-III of Fig. 2 and illustrating the construction of certain of the grate members of the overfeed grate section;

` V-V of Fig, 4 is a transverse sectional view taken von' the line IV-IV of Fig. 2; and,

Fig. 5 is a sectional view taken on the line Fig. 2 and killustrating the means for operating the overfeed grate section.

According to the preferred embodiment of my inventionwhich is shown on the accompanying drawings, I provide' an underfeed stoker section vof alternately-arranged retorts and tuyere rows. and having ymain ramsl for feeding fuel to the retorts and` secondary rams forfeeding'fuel longitudinally of the retorts and also upwardly and later"- ally onto the tuyererows. I also provide an overfeed grate section ydisposed transversely of the lower end of the underfeed section which comprises at least one series of grate members pivotally connected together in endto-end relation and extending in the general direction of the fuel feed. At least the rst grate member of the series'is supported for straight reciprocatory motion in the direction of the fuel feed so that the lanes of green coal and burning material may retain their proper relation and the ash will be positively moved away from the end ofthe underfeed section. The number and length of the grate members which reciprocatev only, l may be varied for stokers of different lengths, i. e., a longer Stoker will have a longer straight reciprocating grate surface and a shorter stoker a shorter surface.

The remaininggrate members of the se-` ries are supported for both bodily movement in the direction ofthe fuel feed and angu! lar -movement about axes extending transversely of the fuel feed. The bodily movementprovides for a continuation 'of the positive progression of the ash and burning material, land the angular movement provides for the breaking down of the lanes and the agitation of the fuel bed so' as to permit the air to penetrate and burn out the remaining combustible. Y

Referring now in detail to the construction illustratedk and particularly to Figs. 1 and 2, it will be observed that l have shown a furnace 10, in which a stoker structure 11A is disposed and divides the 'furnace into a combustion chamber 12 and an air chamber 13. Air is supplied'to the chamber by a vsuit- Vto the retorts. `The overfeed grate section comprises a plurality of series of grate members 19. The grate members of each series v19 are indicated by the reference numerals 2O, 21, 22, 23, 24, 25 and 26 and are pivotally 'l connected together in end-to-end relation by means ofsuitable pins 27.

The underfeed section 1s supported at its upper end by a transverse I-beam 28, and at its lower endA by pillars 29, which latter are in turn supported by a second I-beam130. The overfeed grate section 16 is supported at its upper end bythe lowerend of the underfeed section' and at lits lower end by a front wall 311of a elinker pit32. The inter i mediate portions of the overfeed grate are Ysupported, bysupporting structureand its operating means, vwhich are both in turn supported from spaced beams 33. Thefbeam's 33 are carried at their upper'ends by the of which-is driven from the primary ram- 36 by a rod 38 and lost motion connection 39. As stated,the overfeed grate section 16 receives the burning material from the un- Y derfeed section. The upperv portion of the overfeed section is so constructed and operates in such a manner as to carry out'the lane burning action commenced on the underfeed section. The first grate member 20 of each of the series is mounted -for straight reciprocatory motion. Each of these. grate members comprises a grate frame 40 which isrectangularin shape and a plurality of" detachably securedopening 44 provided in the lower ends of thek lugs 42, and supporting rollers-45 are secured tothe outer ends of these pms. The rollers yare 'mounted for movement within guide- Vways-46 which latter are secured to spaced angle members 47 extending from the underfeed section.

The grate members 21 of each series comprise grate frames 50, and grate bars 51 detachably secured within th-e frames. The rear ends of the frames are provided with spaced downwardly-extending lugs 52, which latter are pivotally connected to the upper end of operating links 53. The lower ends of the links are pivotally connected to a rod 54 extending transversely beneath they stoker and supported by the outer ends of lever arms 55. The inner ends ofthe lever arms are keyed to an oscillating shaft 56 which extends transversely of the stoker and is journalled in suitable supporting standards 57 carried by the beams 33 (see Figs. 1, 2, 3, 4 and 5). n

Oscillatory motion is imparted to the shaft 56 by means of a lever arm .58which is keyed at its upper end to the shaft 56 and pivotally connected at its outer end to the one end of a connecting rod 59. The other end of the connecting rod is pivotally connectedl by a pin 60 to a lever arm 61, which latterV is keyed at its upper end to an oscillating power shaft 62. The power shaft is sunported for oscillatory motion by` bearings 63 mounted on supporting standards 64 which are carried vby the beams 33.' (See also Fig, 4.)

The grate members 422 also compri'serectangnlar grate frames 65 and grate bars 66 detachably secured within the framet The sides of the grate frames (S5-are provided at their rearendswith extensions 67 the under surface of which is formed flat andrests upon rocker-likesupports 68. The' rocker-like supports are pivotally supportedbyshafts 69? which extend transversely underneath the overfeed: grate and are carried by the upper' ends of the supporting standards 57. kThe rocker-like supports permit the grate member 22'to'moveboth1 in the direction of fuel feedand angularly about axes V,extending transversely of the feed'. o

'llhe grate members 23 of each series comprise grate frames 76 and grate bars 71 de tachably secured` Within thel frames, and these grate fra-mes are supported merely at their ends by their'pivotalconnections withV the grate members 22 and grate members 24,

respectively.

TheI grate members 24 comprise grate.

frames 72 and. grate bars 73 detachably secured within the frames. rllhe sides .of the.

grate frames 72 areprovided with downward extensions 74, vand the lower ends ofthese extensions are keyed tothe power shaft 62. Y The grate members- 25 comprise lgrate frames 7 5 and grate bars 76 detachablysecured within the frames, and the rear ends `W-hliclila'tter are carried by the I-beam 34.

- rPhe last grate member` of each series comprises grate lframe v81 andv grate bars-82 detachably secured withinv the frame. The grate is slidably supported at its rea-r end by the upper surface of anV air and water supply casting 83,whi`ch latter is supported byA the front wal131 of the clinker pit. 1-

kThe grate bars20, 21, 22,23, 24, 25- and 26 are each provided along their lateral faces with` vertical grooves 84,Y which provide for the passageV ofi-airfrom the `air chamber 13V to the fuel bed supported byV the overfeed grate section. v

The power shaft 62`Iisoscilla-ted means of a lever arm 85 which iskeyedto the shaft 62 and operatively connected at"its.ou ter end toa connecting'rod arrangement 86. The connecting. rod arrangement extends out-` roo wardly of VtheV furnacel and is driven` from a e suitable electric motor 87. f

Oseillatory movement of thepowers-haft(y will'result in a tilting motion ofthe grate members24', about anaXis whichis trans-A verse-to thedirection of fuel feed. By reason Y otal connections between all of the grate members, the remaining grate members will be moved bodily in the direction of the fuel feed and the grate members 23 and 25 will also move about aXes extending transversely -of the fuel feed. The floating supporting links 78 will permit the grate members 26 to also move angularly with respect rothe fuel-supporting surface.

By reason of the lever arm (il, connecting rod 59, level' arm 58, shaft 56, arms 55 and links 53, oscillatory. motion of the Vpower shaft 62 willalso result in an angular-movement of the grate members 21 and 22. The degree of angular movement imparted to the grate members 2l and 22 may be varied with respect to the degree imparted to the grate members 23, 24, 25 and 26- AsY shown, theV leverarm 6l is provided with a vplurality of openings 9.0. r"'he connecting rod 59 maybe connected to the lever armGl at any one of a number ofv points by inserting the pinv within any desired one of the openings 90, thereby obtaining any desired length of eifactive lever arm. 1

lThe operation of my improved progressive feed stoker will be apparent from the foregoing description. rllhe green coal is fed from the hopper 35 and into the upper ends of the retorts 17 by means of the primary rams 36. rlhis coal is forced lonigtudinally of the retorts andupwardly and laterally over the sides thereof and onto the tuyre rows 18 by means of the secondary rams 37. As stated, the volatiles are' largely liberted from the coal while it is within the retort and such volatiles rise upwardly and combine with the air emitted from the adjacent tuyre rows to produce combustion. The solid carbons are forced onto the tuyre rows where they combine with the air emitting therefrom to produce combustion. As stated, this operation can be referred to as lane burning, lanes of green coal within the retort and lanes of solid carbon on the tuyre rows.

The green coal-is fed into the ends of the retorts in excess of that which can be burned on the underfeed section. 'The excess green coal is forced out of the ends of the retorts and onto the overfeed gratesection. By reason of the straight reciprocatoryvmotion of the upper portion of the overfeed grate section, these lanes are fed downwardly in the direction of fuel feed without disturbing materially their formation. The laneburning commenced on'the underfeed section isrtherefore carried out on the upper portion of the overfeed section. As thecoal feeds downwardly from the ends of the retorts, the volatiles willbe driven off'and these volatiles will combine with air emitting from theadjacent portions of the overfeedgrate section. Theresulting solid 'carbons will spill laterally from the coal lanes onto-the adjacent portionsof the yoverfeed grate section and there be burned in the same manner as on the tuyerek Y ash, this latter being due to the porous condition of that portion, of the fuel bed. y

' It will therefore be seen that the upper portion 'of theoverfeed grate section provides for the same method of burning that is carried out on the underfeed section, and at thesame time lthe reciprocatory motion also provides for the positive and contnuous movement of the ash from thetuyere rows. Also, as the lengths of that portion of the overfeed grate section which provides this continuation of the lane burning and the positive movement of the ash can be varied, it will therefore be seen that I have provided a construction which enables a progressive feed stolzery to be madeA in any required lengths and at the same time obtain the beneficial results required.

`The lower part of the overfeed grate section has a combined movement, Ii. e., the grate members move both bodily in the directcn of fuel feed to provide for the positive and continuous movement of theV fuel bed and alsormove angularly about axes extending transversely of the fuel feed so as to agitate the fuel feed and thereby provide for the breaking down of the lanes at the proper point. Such agitation also provides for the breaking up of any clinker formation. The overfeed grate also provides for the positive admission of air-to the fuel bed so as to effectively burnout the remaining` combustible prior to its reaching the ash disposal appa-ratus.v

,. As the degree of angular movement imparted to oneportion of the overfeed grate section may be varied with respect to the degree of such` motion imparted to another portion of the overfeed gratesection, it will be readily seen that l have provided an overfeed grate section which is extremely flexible in operation', and by reasonof this fact coals of varying characteristics may be effectively and eiiiciently burned.

it will be observed that in the accompanying drawings l have shown the underfeed section, the overfeed section, and the straight eciprocatory portion o f the overfeed .secficn as being of certain relative lengths. lt isto beimderstOOd, however, that the showing `is merely for the purposes of illustration and-that'the respective lengths of these portions of the progressive feed stolzer shown may be varied at will withoutrdeparting Vfrom the scope of the present invention.

- While IV have shown my invention in but one form, it will-.bezobvious to those skilled 1n the art that it is not so limited, but is susceptible of various changes and modifications Without departing from the spirit thereof, and I desire, therefore, that only such limitations shall be placed thereupon as are imposed by the prior art or as are specically set forth in the .appended claims.

I'Vhat I claim is:

l. In combustion apparatus,'the combination with an underfeed stoker section comprising alternately-arranged `retorts and tuyre rows, and means for feeding fuel to one end of the underfeed section; of an overfeed section disposed to receive the burning material from the other end "of the underfeed section and comprising a series of grate members pivotally connected together in end-to-end relation and extending. in the direction of fuel feed; means for supporting the first grate member considered in the direction of fuel feed forreciprocatory movement bodily in the direction of such feed; and means `for imparting a combined oscillatory and reciprocatory motion to some of the reniaining grate members of the series.

Q. In combustion apparatus, the combinay tion with an underfeed stolzer section comprising alternately-arranged retorts and tuyre rows, and means for feeding fuel to one end of the underfeed section; of an overfeed section disposed to receive the burning material from the other end of the underfeed section and comprising a series of grate members pivotally connected together in endto-end relation and extending in the direction of fuel feed; and means providing for reciprocatory movement of all of the grate members forming the series bodily in the direction of fuel feed and including means providing for the oscillation of at least one of the grate members of the series about axes Vextending transversely of the direction of fuel feed.

3. In combustion apparatus, the combinastraight reciprocatory motion only in the direction of such feed; and means for imparting an angular motion about axes extending transversely of the fuel feed, to at least one of the remaining grate'members of the series.

4. In combustion apparatus, the combination withan underfeed stoker section comprising alternately arranged retorts and tuyre rows and means for feeding fuel to one end of the underfeed section; of an overfeed grate section disposed to receive the burning fuel from the underfeed section and underfeed section and comprising a series of grate members pivotally connected together in end-to-end relation and extending in the direction of fuel feed; means for supporting the first grate member considered in the direction of fuel feed, for straight reciprocatory motion only in the direction of such feed; and means for imparting an angular motion about axes extending transversely of the fuel feed, to of the remaining grate members of the series.

5. In combustion apparatus, the comb-ination with a coking structure and means for feeding fuel to the coking structure of an at least one overfeed .grate section disposed to receivethe 'f burning fuel from the coking structure and comprising a series of grate members pivot- A ally connected together in end-toend relation and extending in the direction of fuel feed; and means for imparting a combined oscillatory and reciprocatory motion to the series of grate members at at least two spaced points and including means for varying the degree of-motion imparted at one of such points with respect to the degree of motion imparted at the other of such points.

6. In combustion apparatus, the combination with an underfeed Stoker section oomprising alternately arranged vretorts and tuyre rows, and means for feeding fuel to one end of the underfeed section; of an overfeed grate section disposed to receive the burning material from the other end of the comprising a series of grate members pivotally connected together in end-to-end relation and extending in the. direction of fuel feed; and means for imparting a combined oscillatory and reciprocatory motion to the series of grate members at at least two spaced points and including means 'for varying the degree of motionimparted at one of such points `with respect to the degree of motion imparted at the other of such points.

In testimony whereof, I have hereunto subscribed my name this 12th day of Se t., 1929.

f DONALD J. MOSSHRT. Y 

